There are a number of medicament delivery devices that are intended for self-administration. Some of these devices are provided with automatic functions such as auto-penetration, auto-injection, auto-withdrawal, just to mention some. However, even if these functions facilitate the administration of medicament, the devices become rather complex to manufacture and there is an increased risk for mal-functioning of a function.
In these aspects it would be desirable in many instances to have manually operated devices that are intuitive and easy to operate and inexpensive. However, for persons with reduced power of the hands and/or reduced dexterity of the hands, manual operation may be difficult because there is required a rather large force for performing a medicament delivery and in particular to overcome the break loose force of a stopper arranged inside a medicament container.
In view of this some devices have been developed for facilitating the handing of a syringe such that less force is required. Documents U.S. Pat. No. 5,336,201 and WO 2002/094343 both display delivery devices having a gripping handle and a lever pivotally attached to the handle, where the lever is acting on either a separate piston that is capable of drawing medicament from a container to a patient (U.S. Pat. No. 5,336,201) or acting on a plunger of the syringe (WO 2002/094343). The drawbacks with the design of the described devices is that they become rather bulky, looking like hand guns, which is not an advantage when a user has to carry the device with him daily nor to use it publically.
WO 2007/132019 relates to a pen-injector that comprises a lever gearing designed to provide increase power during manual injection. The device also allows dose setting. A drawback is the thin shape with a push button at the distal end, which make it difficult for the manually impaired to operate.
There is thus room for improvement regarding manually operated medicament delivery device which are provided with force assistance.